Technical Field
The present invention generally relates to a system and method for raising and lowering roller shades and more particularly to system and methods to mitigate component damage or user injury during use.
Background Art
One type of motorized window treatment is a motorized roller shade. A typical motorized roller shade includes a flexible shade fabric wound onto an elongated roller tube. The roller tube is rotatably supported so that a lower end of the flexible shade fabric can be raised (i.e., wound) or lowered (i.e., unwound) by rotating the roller tube. The roller tube is rotated by a motorized drive system.
Motorized roller shades can be automated to automatically raise and lower. Unlike manual shades, where the user walks up to the window and opens or closes the shade using a cord or by pulling on the shade, motorized shades make it easy to open or close one or multiple shades with the touch of a button, or by programming them to automatically move at a specific time with no user interaction. In this regard, automation can be used to help minimize heat gain, prevent glare, or protect furnishings from harmful Ultra Violet rays.
Due to the automated nature of movement of motorized window treatments, a user may not realize if there is an obstruction. An obstruction may interfere with the shade and limit its movement. If a shade is lowered and encounters an obstruction, the shade fabric normally will bunch up. Damage normally does not occur to either, the motor nor an occupant of the room during lowering. However, when the shade is raised, the presence of an obstructing object may cause damage to the motor or brackets, for example, and poses an injury risk to the user. The amount damage, in some cases, may be directly related the amount of torque created.